Processing biological material for flow cytometry evaluation for virus particles

In a method for processing biological materials for flow cytometry evaluation for virus particles, a mixture including biological material and purification particles is centrifuged to prepare a centrifuged composition including a supernatant that may be further processed prior to the flow cytometry evaluation. The purification particles include porous cores functionalized to capture smaller-size impurities in a biological material sample and a porous size-exclusion shell surrounding the core to exclude larger-size components of the biological material from entering into the core. Multiple samples may be processed in multi-sample processing units. A product may contain a sealed container with the unit quantity of purification particle in a storage liquid and a kit may include such a sealed container and a centrifugal filter.